ezobens

This is perhaps a dumb question but why is the humidity set to 0%?
Is the air in the dyno really that dry?
Unless you're testing in Death Valley or something, you will realistically never see 0% humidity.
Just curious.
Elm

ajrothm

You know I did that right??

My engine made 662hp/675tq SAE on Vortecpro's dyno, he shipped it to me, I unboxed it, put it on local Superflo 901 dyno, it made 657/670 SAE... We even made pulls uncorrected and it was 615 ish...this was on a rainy/humid day in a non air conditioned dyno cell...This is a very reputable race engine shop here in Houston that builds/tunes a lot of high end stuff. The dyno's numbers usually match up to trap speeds in winter air at RPR.


Pretty damn close to me...

Now my car has never shown that power on the strip...mainly because of the heavy drive train, full accessories, smaller headers, converter, etc etc.... It shows about 585 hp in my tank. I'm sure in a true track car with a real converter, no exhaust, no accessories etc, it would show that 650....

TheGreek!

How much power would it make if it had higher compression (like 10.5 to 11.5 to 1) and rectangular port heads? I've always wondered how a low compression 454 w/oval port heads can make more power than a 1970 LS6 (11 to 1, square port closed chamber heads) or LS7 (12.5 to 1, square port open chamber heads). It can't be simply just because of a more modern cam and intake than the LS6 and LS7 but if it is then what kind of power would an LS6 or LS7 make with a modern cam and intake? 700 + horsepower? It would have to be if a 9 to 1 oval port 454 is making 650 horsepower. I would assume that the LS6 and LS7 would make a lot more power than a 9 to 1 compression 454 with oval port heads. If I'm wrong then someone please tell me why because I'm contemplating a 454 build with rectangular port open chamber heads with 10 to 1 or 11 to 1 compression.

Neil B

The big rectangular port heads would only make more power at higher rpm ranges (think solid roller and compression to match). Mark's oval ports are probably flowing 330+ cfm with a big enough runner to support 6,500 to 7,000 rpm on a 454. The rectangle head would most likely not make additional power under 6,500. You would really have to spin the motor with GOOD rectangle heads to make more power. The added compression never hurts if you are running the fuel/cam timing to support it. Just my .02.

v2racing

Exactly! A pair of oval port heads using a 2.19 valve with good portwork, chamber work and seat work, will have better flow than a stock rectangular port head, especially at low and mid lifts, while having better velocity to make a wider powerband and still produce more peak HP and torque.

Mike

DO2G

Vortecpro built me a 622HP 468 BB for my 78 corvette....it’s awesome and extremely fun to drive!

Big2Bird

I bet. How you doing?

Vortecpro

That's a good question. The humidity in my dyno cell this time of year is around 20 % quite dry in Colorado. The correction factor J607 STP again is 29.92 absolute barometer, 60 degrees dry air, this correction factor is applied to the observed in the room dyno HP for comparisom purpose's, and if the dyno is calibrated, its extremely close from SF dyno to dyno. I hope this explains this.

Vortecpro

I agree with this above.
My dyno numbers from my shop were:
661 HP
I believe 672 TO
Super Flow 901 dyno

Owens dyno numbers Houston:
657 HP
675 TQ
32 degrees total timing
Super Flow 902 dyno (very important detail)

Its my opinion 34-35 degrees total timing would have produced over 660 HP @ Owen's dyno facility, 32 degrees total produced more TQ less HP as I always see on my dyno. You mentioned the knock sensor was picking up a knock above 32 total, well after seeing how Owen's runs the water system on their dyno this makes sense, this was talked about with former Super Flow employees, and they felt this water inlet system was inadequate. But make no mistake you did a good job on the dyno test, and especially with the car.

Vortecpro

More head pictures, we move to the block next.

Rebelrob

Exactly.


ajrothm you have given Mark good street cred, (No Pun Intended) with your 496 cid many many, times and you got the E.T's to prove it. Near mid 10 seconds E.T.s with iron heads, air gap intake, and AC if I remember correctly. Road trip to east coast and back, etc. She is a big heavy girl also.

ajrothm

Yeah... it’s been cross country twice. 23k miles on the engine now. Compression is still 200+ psi across the board. It’s had the tar beat out of it for 9 years...It’s been the most reliable street motor I’ve ever had, basically maintenance free, valve covers haven’t been off in 8 years.

It hasn’t been to the track in few years but I’m still busting *** on the street with it. It’s funny when I pull on Hellcats with it on the street. Lol....

Some day, I’m gonna have Mark build me a BIG motor when this one gives up but....it just keeps on going and going.

Neil B

I see some nice bowl work on the exhaust side!

Vortecpro

Block work almost complete:


1. Block prep 2.5 hours
2. Line hone 2.9385-2.9386
3. Deck 9.780 exact
4. Bore .053

Vortecpro

So we move on to the rods. Due to a shortage of suitable factory GM rods we used a 6.385 Eagle rod, now some will say "it doesn't make sense to rebuild stock rods after you buy bolts and pay for machine work" well that's not exactly right. Pay close attention Eagle and Scat rod users. Our Eagles rods measured big on the big ends, so we resized them, and here's what we found. What your seeing is the parting surfaces are not 90 degrees to the sides, this revealed its self when cutting for resizing. This can cause severe tapper in the bore, and other problems.

Vortecpro

So we resize the rods and get them in spec 2.3247. So now we have 8 rods we can use right? Not exactly, now we take a look at the small end, guess what.....its small, better small than too big, so we have to hone that to .0008-.0009 clearance.

Vortecpro

The crank is next, we will grind it 010 010 and throw it on the balancer, well.........not exactly.................

Vortecpro

My production GM cranks get wet magged first, the counter weights get bull nosed, the overall counter weight diameter is cut down .300-.500, the crank is ground to the housing bore spec, while being indexed and stroke is set at exactly 4.00, this is the advantage over a cheap aftermarket crank, stroke, index, journal sizing, straitness, are always a problem with a cheap aftermarket crank, you might as well re grind it, if.......you can find someone who can and will do it right.

Vortecpro

The piston we will use in our 467 build, Mahle 28 CC dome. Final compression will be 10.3.

69ttop502

Great stuff Mark! The attention to detail is amazing!